V. Structure of Haz-Map

Haz-Map is a relational database of hazardous
chemicals and occupational diseases. The database currently contains 10,133 chemical and biological agents,
240 diseases, 121 findings (signs &
symptoms), 261 jobs, 243 job tasks, 54 industrial processes, 624 industries, and
27 non-occupational activities. The relationships of the tables in the database
are shown in Figure 2. When available, standard classification systems were
used: Standard Occupational Classification (SOC) system for jobs, the North
American Industry Classification System (NAICS) for industries, and the
International Classification of Diseases (ICD-9) for diseases.

Diseases

(Epidemiology)

Chemicals

(Industrial Hygiene)

Figure
2: Two levels of information in Haz-Map: diseases and chemicals; The "Toxic
Chemicals" table includes biological agents like grain dust and latex
rubber.

Notice the bi-directional arrows indicating that users
can find all chemicals linked to each disease and all diseases linked to each
chemical. Similarly, they can also see all findings of a disease or all
diseases with the finding.

Chemical
and biological agents
in the database are
linked to industrial processes and non-occupational activities. Linkage
indicates the potential for exposure to the agent. As mentioned earlier, each
agent in the database is flagged for adverse effects including asthma,
pneumonitis, neuropathy, anemia, hepatotoxicity, and skin sensitization.

Occupational
diseases in the database are linked to findings (signs and symptoms of the
disease) and hazardous job tasks. Hazardous job tasks increase workers risk for
significant exposure and subsequent disease. Linkage between job tasks and jobs
or industries indicates an increased likelihood for workers in these jobs or
industries to engage in the hazardous job tasks. In this database, chronic
occupational diseases are linked to both jobs and industries, while acute
diseases and infectious diseases are linked only to jobs. Cancers are not linked
to jobs, industries or findings.

Diseases
are also linked to Agents. Linkage between a chemical or
biological agent and a disease indicates that sufficient exposure to the agent
is associated with increased risk of developing the disease. For chronic
diseases, linkage between an agent and a disease means that a causal
relationship has been determined based on human case reports or epidemiological
studies. Carcinogens are linked only if they have been designated as known human
carcinogens by IARC. In some cases, IARC does not list the target organs, but
Haz-Map follows the interpretation published in Schottenfeld's Cancer
Epidemiology and Prevention, 3rd Ed. [Siemiatycki,
p. 326-7]. Acute diseases, for the most part, are also linked to
chemicals based on reports of cases in humans.

Diseases
are included only if there is sufficiently robust evidence that occupational
exposure can cause the diseases, and therefore, that the diseases can be
prevented by good occupational hygiene practices.From the point of view of epidemiology and occupational disease
surveillance, what are the most common work-related diseases? For each
occupational disease, which jobs have the highest risk? Within each job, what
are the job tasks or conditions that put the workers at risk?

VI.
Updating the Database

Work
during the last several years has been focused on adding chemicals to the
database. Haz-Map is updated continuously as new agents are added every day and
compared to agents in the database. 2400 chemicals from the HSDB database were added in 2010. Since then,
about 5000 chemicals from the SEM database were added. The SEM database contains
over 15,000 chemicals/trade names based on records of chemicals used at U.S.
federal facilities for nuclear weapons research and development during the Cold
War. Many of these chemical are rarely used, and information is scarce. Whenever
possible, these chemicals are compared to more well-known chemicals with similar
structures. The SEM database also includes many common chemicals of
biological origin that were not originally in Haz-Map. It was decided to add
rather than ignore these biological agents (monosaccharides, amino acids,
proteins, vitamins, etc.) because they demonstrate that all chemicals are toxic
at sufficient dose, and their structures can be compared to other chemicals
already in the database. Haz-Map does not include drugs unless they cause
occupational diseases, e.g., asthma or contact dermatitis. Generally, it does not include alloys or
commercial mixtures.

ACGIH
publishes every year Documentation of the Threshold Limit Values, Supplement
to the 7th Edition, and changes in these documents are added to the
database. See this page for the 2014 changes. IARC
published several important monographs in 2012 that were added. See the
bottom of this page for details. As mentioned earlier,
a review of the
literature was completed in 2011, and is described on this page.
As a result of that review, the categories "More Research Needed" and
"Reproduction and Development" were added to the other ten categories
of diseases. Textbook references are reviewed when new textbook editions are
published. Several literature reviews of occupational medicine journals have
been completed (1998-2002, 2005-2008, 2008-2011). 284 papers were selected and
read in 2008 and 256 in 2011. For example, in 2008 the following number of
journal articles in specific topics were read: Beryllium (12), Respiratory
Diseases (24), Solvents (16), Neurodegenerative Diseases (4), Pesticides (4),
Benzene (2), Welding (7), Toxicology (3), Cancer (49), Metals (28), Asthma (30),
Pulmonary Function Tests (7), Jobs (15), Farming (13), Silica (21),
Hypersensitivity Pneumonitis (9), Coal Workers' Pneumoconiosis (4), and Other
(36). These reviews resulted in changes to chemical and
disease profiles in Haz-Map, often with hyperlinks to the
journal articles.

In
October of 2014, the author reviewed the ATSDR Web Page "Camp Lejeune,
North Carolina" (http://www.atsdr.cdc.gov/sites/lejeune/tce_pce.html).
This web page lists reported health effects of five chemicals
(trichloroethylene, perchloroethylene, benzene, and vinyl chloride) and has 36
references. The assignment involved reading the papers and finding eight other
papers that were used in the report. As a result of that review, "Angiosarcoma
of the liver" as a unique form of occupational liver cancer was added to
Haz-Map. Previously, vinyl chloride had been linked to "Liver cancer."
After the review, "Vinyl chloride" was linked to "Angiosarcoma of
the liver," and "Liver cancer" was linked to "Aflatoxins," "Plutonium," and "Viruses (hepatitis
B and hepatitis C)."

Chemicals
that don't inherit the properties of particular metal compounds or known classes
of chemicals could be prioritized for study. Possible examples in Haz-Map
include chemicals classified in "other" categories like "Other Nitrogen Compounds" or
"Aromatic Compounds (Nitrogen)."

Industrial
hygiene has improved greatly in the U.S. in the last 70 years. Before 1947, the recommended benzene standard was
100 ppm. Now it is 0.5 ppm. Hazardous
substances banned between 1972 and 1991 include: all agricultural uses of DDT
(1972); thallium rodenticides (1972); most uses of aldrin & dieldrin (1974);
production of benzidine for commercial sale (1974); asbestos in insulation
materials (1975); leaded gasoline in new vehicles (1975); most uses of mirex
(1977); production of PCBs (1977); sale of lead-based paint to consumers (1978);
most uses of BHC, chlordane and heptachlor (1978); all uses of chlordane (1988);
and use of mercury in exterior paints (1991).